This was a utility for flipping between intrinsic and debug record mode
-- we don't need it any more. The "IsNewDbgInfoFormat" should be true
everywhere.

Start removing debug intrinsics support -- starting with the flag that
controls production of their replacement, debug records. This patch
removes the command-line-flag and with it the ability to switch back to
intrinsics. The module / function / block level "IsNewDbgInfoFormat"
flags get hardcoded to true, I'll to incrementally remove things that
depend on those flags.

Add per-property has<Prop>/set<Prop>/reset<Prop> functions to
MachineFunctionProperties.

Moves `MIRPRinter` and `MIPrinter` fields into a new `MFPrintState`
struct. Turns methods into independent functions.

- This slightly simplifies the code.
- In the future this will allow to pass the state around to other printing functions
   without the need to expose classes in the public headers.

std::tie simplifies the lexicographical comparison while making the
code a little more consistent within MIRPrinter.cpp as we have a very
similar comparison functor in MIRPrinter::convertCalledGlobals, about
30 lines below the code this patch touches.

- Move `MIPrinter` class to anonymous namespace, and remove it as a
friend of `MachineBasicBlock`.
- Move `canPredictBranchProbabilities` to `MachineBasicBlock` and change
it to use the new `BranchProbability::normalizeProbabilities` function
that accepts a range, and also to use `llvm::equal()` to check equality
of the two vectors.
- Use `ListSeparator` to print comma separate lists instead of manual
code to do that.

During the transition from debug intrinsics to debug records, we used
several different command line options to customise handling: the
printing of debug records to bitcode and textual could be independent of
how the debug-info was represented inside a module, whether the
autoupgrader ran could be customised. This was all valuable during
development, but now that totally removing debug intrinsics is coming
up, this patch removes those options in favour of a single flag
(experimental-debuginfo-iterators), which enables autoupgrade, in-memory
debug records, and debug record printing to bitcode and textual IR.

We need to do this ahead of removing the
experimental-debuginfo-iterators flag, to reduce the amount of
test-juggling that happens at that time.

There are quite a number of weird test behaviours related to this --
some of which I simply delete in this commit. Things like
print-non-instruction-debug-info.ll , the test suite now checks for
debug records in all tests, and we don't want to check we can print as
intrinsics. Or the update_test_checks tests -- these are duplicated with
write-experimental-debuginfo=false to ensure file writing for intrinsics
is correct, but that's something we're imminently going to delete.

A short survey of curious test changes:
* free-intrinsics.ll: we don't need to test that debug-info is a zero
cost intrinsic, because we won't be using intrinsics in the future.
* undef-dbg-val.ll: apparently we pinned this to non-RemoveDIs in-memory
mode while we sorted something out; it works now either way.
* salvage-cast-debug-info.ll: was testing intrinsics-in-memory get
salvaged, isn't necessary now
* localize-constexpr-debuginfo.ll: was producing "dead metadata"
intrinsics for optimised-out variable values, dbg-records takes the
(correct) representation of poison/undef as an operand. Looks like we
didn't update this in the past to avoid spurious test differences.
* Transforms/Scalarizer/dbginfo.ll: this test was explicitly testing
that debug-info affected codegen, and we deferred updating the tests
until now. This is just one of those silent gnochange issues that get
fixed by RemoveDIs.

Finally: I've added a bitcode test, dbg-intrinsics-autoupgrade.ll.bc,
that checks we can autoupgrade debug intrinsics that are in bitcode into
the new debug records.

This change splits out the renaming and comment updates from #129612 as a non-functional change.

Remove `TargetIntrinsicInfo` class as its practically unused (its pure
virtual with no subclasses) and its references in the code.